Topic 6 Plant Structures and their Functions Flashcards
What is the word equation for photosynthesis?
Carbon dioxide + water → glucose + oxygen (in the presence of light and chlorophyll).
Where does photosynthesis take place in a plant cell?
In the chloroplasts.
What is the role of chlorophyll in photosynthesis?
Chlorophyll absorbs light energy needed for photosynthesis.
Name two factors that affect the rate of photosynthesis.
Light intensity, carbon dioxide concentration, temperature.
What is the function of xylem vessels in a plant?
To transport water and minerals from the roots to the leaves and provide structural support.
What is the function of phloem vessels in a plant?
To transport sugars (glucose) and other organic nutrients from the leaves to other parts of the plant (translocation).
What is transpiration?
The process by which water evaporates from the leaves of a plant, pulling water up through the xylem vessels.
How is water absorbed by plant roots?
Water is absorbed by osmosis from the soil into the root hair cells.
How are root hair cells adapted for water absorption?
Root hair cells have a large surface area and thin walls to absorb water more efficiently.
Why do plants in hot, dry climates have small or waxy leaves?
To reduce water loss through transpiration.
What is the role of stomata in gas exchange?
Stomata allow gases (CO₂ and O₂) to move in and out of the leaf, and they also help regulate water loss.
How do guard cells regulate the opening and closing of stomata?
Guard cells swell to open stomata when water is plentiful and shrink to close stomata when the plant needs to conserve water.
What is the role of auxins in plant growth?
Auxins promote cell elongation and help plants grow towards light (phototropism).
What is phototropism?
The growth of a plant towards light, controlled by auxins.
What is gravitropism (geotropism)?
The growth of a plant in response to gravity. Roots show positive gravitropism (grow down), and shoots show negative gravitropism (grow up).
